ABSTRACT
L-selectin is constitutively expressed on the microvilli of leukocytes. Cell surface levels of L-selectin are regulated by metalloproteinase-dependent cleavage of the extracellular domain following leukocyte activation (Smith 2008). Th e intracellular tail of L-selectin binds to calmodulin, and to the actin cytoskeletan via α-actinin and the ezrin/radixin/moesin protein family. Th e balance between these competing intracellular interactions may infl uence the proteolytic cleavage of the extracellular domain (Ivetic and Ridley 2004). Th e extracellular domain of L-selectin binds both PSGL-1 and glycoproteins found on specialized high endothelial venules of peripheral lymphoid tissue (Smith 2008).
